1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method, and in particular relates to image forming art for an image forming apparatus that attaches a coloring material-containing ink and a treatment liquid onto a medium so as to form a desired image on the medium.
2. Description of the Related Art
In recent years, inkjet recording apparatuses have become widespread as image forming apparatuses for forming images such as pictures and documents on media. In an inkjet recording apparatus, nozzles provided in a print head are driven in accordance with data, so that ink droplets are ejected from the nozzles, whereby a desired image is formed on a medium.
Depending on the type of the medium and the type of the ink, if the deposited ink permeates through the medium, then smearing or spreading out of the dots formed may occur, causing a marked degradation in the quality of the image formed. Moreover, if an ink droplet is ejected so as to overlap (contact) with at least part of another ink droplet already on the medium, then a phenomenon in which the ink droplets become mixed together (unite with one another), namely, deposition interference, can occur. To prevent image degradation due to such smearing or spreading out of dots, deposition interference and so on, an inkjet system has been proposed according to which ink and a treatment liquid that can react with the ink are deposited onto a medium, and the ink and the treatment liquid are made to react with one another on the medium, whereby smearing and spreading out of dots, and ink deposition interference are prevented. Moreover, an inkjet system has been proposed according to which, with regard to fixing the ink, after having been deposited onto the medium, the ink is irradiated with a radiation such as an ultraviolet radiation, so as to promote curing and fixing of the ink.
With an inkjet recording method, recorded article, and inkjet recording apparatus described in Japanese Patent Application Publication No. 10-287035, the configuration is such that printing is carried out by attaching a reaction liquid containing a photopolymerization initiator and an ink composition containing an acrylate monomer and an oligomer onto a recording medium, whereby print smearing and print irregularities are suppressed, and color bleeding, which is uneven color mingling at border regions between different colors in the color inkjet recording method, is prevented.
With an inkjet recording method described in Japanese Patent Application Publication No. 2003-12971, the configuration is such that printing is carried out by attaching an ink composition containing 30% to 98% by mass of a polymerizable compound and a coloring material, and a reaction liquid containing a polymerizable compound and a polymerization initiator onto a recording medium, whereby print smearing and print irregularities are suppressed, and color bleeding, which is uneven color mingling at border regions between different colors in the color inkjet recording method, is prevented.
Moreover, with an inkjet recording apparatus, image forming method, and ink composition described in Japanese Patent Application Publication No. 2000-135781, the configuration is such that a first ink composition and a second ink composition are mixed together and cured, so as to form at least part of an image, whereby a highly detailed clear image can be recorded even on plain paper that has not been subjected to special treatment.
With the inventions described in Japanese Patent Application Publication No. 10-287035, Japanese Patent Application Publication No. 2003-12971, and Japanese Patent Application Publication No. 2000-135781, art in which a radiation-curable ink is separated into two liquids is disclosed. However, in the case where the degree of the mixing of the two liquids is insufficient, or the case where the balance between the two liquids is poor in places, curing of the mixture of the two liquids is inadequate due to such causes, and hence there is a possibility that uncured mixture (reaction liquid) or ink remains on the medium.